Electric switch and operating means therefor



' Dec. 3, 1929. G. R. TOWNSEND 1,738,406

ELECTRIC SWITCH AND OPERATING MEANS THEREFOR Filed June 18, 1925 Fig.9.

Inven'lior- George R.Townsend His Attorngg Patented Dec. 3, 1929 UNITEDSTATES PATENT OFFICE GEORGE R. TOWNSEND, OI? SCHENECTADY, NEW YORK,ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELEGTRIQSWITCH, AND OPERATING MEANS THEREFOR Application filed June 18,

My invention relates to improvements in electric switches, and inparticular to improvements in the operating means whereby the switchcontact mechanism is quickly opcrated to and from its definitepositions, as

for example to and from the closed position of the switch. It isdesirable that the movement of the contact mechanism be very quicklyaccom- W plished both in opening and in closing an electric circuitsince destructive arcing at the switch contacts is thus.eitherminimizedor entirely prevented. It is also desirable that after an operator hasbegun the opening or closing movement of the switch handle and hasproceeded with the movement up to a certain position that the movementof the switch contact mechanism shall not commence until the handle hasbeen moved to the certain position, whereupon the quick movement of thecontact mechanism begins and the contact mechanism proceeds to itsdefinite position regardless of further movement of the handle in thesame direction. Pitting of the contact mechanism due to a slow movementof the handle is thus avoided since the speed of operation of thecontact mechanism is entirely independent of the speed of operation ofthe switch handle. A

Quick action operating means for electric switches as ordinarilyconstructed have heretofore provided some sort of a resilient conncctionsuch as a spring between the switch operating member and the switchcontact mechanism so as to obtain a quick closing and a quick opening ofthe switch. In such of that type of switches with which I am familiar,in case the spring breaks or is rendered otherwise inoperative, theswitch cannot be operated and that is objectionable, particularly whenthe switch is employed for controlling electric motors.

One of the objects of the invention is the provision of an improvedquick action operating means for electric switches, whereby in case offailure of the part of the operating mechanism which effects the quickaction feature, the switch may nevertheless be operated at will so thatthe circuit controlled by the switch may be opened and closed and 1925.Serial No. 38,075.

otherwise governed although not with the desired snap action.

The present invention is particularly applicable to switches required tocontrol substantial amounts of power such as motor starting switches andthe like. In such switches ruggedness of .construction is particularlyimportant because of the severity of the service to which such switchesare ordinarily subjected, and simplicity of construction and arrangementis also of great importance in order to obtain the desired reliabilityof operation and the necessary economies for large scale production.

In the embodiment of my invention which I now regard as the preferredform, I provide an improved, simple, rugged and reliable quick actionoperating means between the switch handle and the switch contactmechanism whereby the above mentioned features to be desired in switchesof this class are ob-\. tained. Among other features of the inventionthere is provided an oscillating member which is connected to the switchcontact v mechanism and is connected to an operating member through aspring which is put under strain during the initial movement of theoperating member and the strain thereof is released to move theoscillating member and the contact mechanism quickly during so the finalmovement of the operating member. The arrangement is such that in casethe spring breaks, or is otherwise rendered inoperative, the oscillatingmember will be operated by the operative member so that the switch. isfully operating although without the quick action feature.

For a better understanding of the invention, reference is had to theaccompanying drawing in which Fig. 1 represents an electric switch inaccordance with the invention, the parts of the switch being in theirrespective positions when the switch contact mechanism is in the openposition. In Fig. 2 the various parts of the switch are shown in theirrespective positions when the switch contact mechanism is in the closedposition. Fig. 3 is a very simplified diagram of a motor control systememploying the electric switch of the invention for connecting anddisconnectin the electric motor to a source of supply. lteferring to thedrawings, the switch contact mechanism comprises a pair of movableswitch contacts 10 which are adapted to cooperate with correspondingstationary contacts 11. The contacts 10 are mounted on and operated bythe shaft 12 of insulating material. The shaft 12 is connected to theoscillating member 13 so as to be operated thereby, by means of a forkedmember 14 secured to the shaft 12 and a pin 15 which is secured to theoscillating member 13 and is arranged to cooperate with the prongs ofthe fork-ended member 14. This oscillating member 13 has its upper endpivotally mounted in the supporting frame 16, and the other end of theoscillating member is connected to the operating member 17 by means of aspring 18 which has one end hooked over the catch 19 on the lower end ofthe oscillating member and the other end thereof hooked over the pin 20connected to one arm of the operating member 17.

he pin 20 connects the operating member 17 and the intermediate member21 which is mounted for rotation about the extension 12 of the shaft onwhich the switch contact mechanism is mounted. This intermediateoperating member 21 is provided with two oppositely disposed arms whichare arranged I to engage the oscillating member 13 when the switch is ineither of its definite positions, that is, the one arm engages theoscillating member when the switch is in the open positlon as indicatedin Fig. 1 and the other arm'engages the oscillating member when theswitch is in the closed position as indicated in Fig. 2. The operatingmember 17 has connected thereto a handle 22 so that the openmg andclosing of the switch will be under the control of an operator.

In order to insure that the switch contact mechanism will make positivecontact in the closed position and not be affected by the shocks classis ordinarily subjected, the resiliently mounted detent 23 is providedfor holding the free end of the oscillating member 13 as shown in Fig. 2and thus securely locking the switch contact mechanism in the closedpositlon. The arrangement of the parts is such that the arm 24 on theoperating member 17 .will engage the catch 23 and release the sa he soas to permit the switch contact mechanism to move to the open positionafter the handle 22 has moved the operating member 17 a predetermineddistance in the opening direction.

- Theoscillating member is also arranged to engage the catch 23 andenforce a quick closing of the switch contacts.

As thus constructed'and arranged, the operation of my invention is asfollows: With the switch contact mechanism in the open position asindicated in Fig. 1, in order to close the switch, the handle 22 will bepulled and jars to which apparatus of this upwardly, thereby rotatingthe operating member 17 in the same direction and putting the spring 18under a strain to close the switch contacts. The arm 24 will release thecatch 23 and the catch will move upward under its spring pressure untilthe projection 25, which has a sloping cam surface, engages with thelower end of the oscillating member 13. The contact mechanism will notimmediately move to the closed position since the closing movement willnot begin until after the pin 20 carried by the one arm of the operatingmember 17 has moved past the line connecting the lower or free end ofthe oscillating member 13, the shaft 12 and the pin 20 and theoscillating member has released itself from engagement with the slopingprojection 25. \Vhen the pin 20 has been moved past this dead centerposition, the strain set up in the spring 18 during the initial movementof the handle 22 will now be effective to overcome the holding effect,of the camshaped projection 25 on the catch 23 and very quickly throwthe oscillating member 13 in a counter-clockwise direction about itsupper pivotal support in the supporting member 16, thereby moving thecontacts 10 very quickly into engagement with the contacts 11 throughthe forked end member 14 and the pin 15 connected to the oscillatingmember 13.

The shaft 12 passes through the slot 26 in the lower end of theoscillating member 13, and when the contact mechanism has been movedinto the closed position the shaft 12 will be in engagement with theleft-hand edge of this slot and thus arrest further movement of thecontact mechanism in the closing direction. It will be obvious that theopening movement of the contact mechanism is likewise arrested by theshaft 12 coming into engagement with the right-hand edge of this slot.When the contact mechanism has been thus moved into the closed position,the lower or free end of the oscillating member 13 will be moved to sucha position that this free end of the oscillating member is engaged bythe projection 27 of the resilient catch 23 so that the switch issecurely locked in the closed position and will not be affected by theshocks and jars to which apparatus of this class is ordinarilysubjected.

In order to open the switch, the handle 22 is pulled downwardly, therebyagain placing the spring 18 under a strain to open the contact mechanismduring the initial movement of the handle. As soon as the pin 20 haspassed the dead center position with reference to the lower end of theoscillating member and the shaft 12, further movement of the handle 22will bring the arm 24 of the operating member 17 into engagement withthe end of the pivoted catch 23 so that the oscillating member is freeto move in the opening direction by reason of the strain set up in thespring 18 during the initial opening moveloo lit)

ment of the handle 22. The parts will now return to their respectivepositions indicated in Fig. 1.

In Fig. 3 the switchvis indicated as controlling the connection anddisconnection of an electric motor 28 from a suitable source of supply:The switch is indicated in very diagrammatic form and the various partsthereof are lettered the same as the corre sponding parts of Figs. 1 and2.

It will be observed that the switch employs comparatively few parts andthat the various parts are of rugged and substantial construction. Inthe open position of the switch there is no strain on the spring 18 andthis is of advantage since the spring is only under strain when theswitch is being used to close the controlled circuit. It will also beobserved that the respective parts of the switch are relatively simplein construction so that the device lends itself very readily to largescale manufacture. A quick opening and a quick closing of the controlcircuit is always effected, regardless of the speed at which theoperator moves the handle 24. It is impos sible for the operator toleave the handle in an intermediate position such that arcing isestablished and maintained at the switch contacts. That is because ofthe fact that during the initial movement of the handle there is noresulting movement of the switch contact mechanism, and as soon as themovement of the switch contact mechanism has started, it is completedregardless of further movement of the handle in the same direction.

In case the spring 18 should break, the switch may nevertheless beoperated through theaction of the intermediate member 21. Thus, inclosing the switch, moving the handle 22 will also move the intermediatemember 21, and after a limited movement thereof the arm 29 will engagethe member 13 and move the same so as to close the switch con- 'tacts.Except for the quick action function obtained by reason of the operationof the spring 18, the operation will be the same as previously setforth. In opening, the arm 30 of the intermediate member will engage theoscillating member 13 and cause the switch contacts to be opened,although not with a snap action.

What- I claim as new and desire to secure by Letters Patent of theUnited States, is:

1. Operating means for an electric switch having switch contact.mechanism operable between two definite positions, comprising anoperating member, an oscillating member connected to said contactmechanism for operating the same between said positions, a springinterposed between said operating member and said oscillating member forimparting a snap action to the contact mechanism in response tomovements of the operating member, an intermediate member operated bythe operating member for operating the contact mechanism to and fromsaid definite positions in response to movements of the operating memberin case offailure of said spring, and a resiliently mounted catchcooperating with said oscillating member for holding the said contactmechanism in one of said positions, the said operating member beingarranged to release said catch during the initial movement of theoperating member to operate the switch.

Operating means for an electric switch having a shaft and switch contactmechanism mounted thereon and operable between an open position and aclosed position, comprising a pivoted operating member, a pivotallymounted oscillating member connected to said contact mechanism foroperating the same between said positions, the said oscillating memberbeing mounted to move about a different pivot than said operatingmember, a spring interposed between the free end of said oscillatingmember and said operating member, the said spring being relieved ofstrain in the open position of the switch and put under strain duringeach movement of the operating member to open and close the switchtoeifect. a snap action in opening and closing the switch, and anintermediate member operated by said oper-. ating member for operatingsaid oscillating member and said switch contact mechanism in case offailure of said spring.

3. Operating means for an electric switch operable between two definitepositions, comprising a pivotally mounted operating member, a pivotallymounted oscillating member connected to said contact mechanism foroperating the same between said positions, the said oscillating memberbeing mounted to move about a different pivot than said opcratingmember, a spring interposed between the free end of said oscillatingmember and said operating member, the said spring being put understrainduring each movement of the point of connection of the spring with saidoperating member toward the line connecting the centers of movement ofsaid members and released to operate the said oscillating member andmove the contact mechanisnfi to one of its definite positions during themove- 'ment of the operating member past the said centers of movement,means operated by said operating member coacting with said contactmechanism for operating said mechanism to and from said positions incase of failure of said spring, and a resiliently mounted catchcooperating with said oscillating member for holding the said contactmechanism in one of said positions, the said operating member beingarranged to release said catch during the initial movement of theoperating member to operate the switch.

4. Operating means for an electric switch having a shaft and switchcontact mechanism mounted thereon and operable between leased to operateed rotation about the axis of said an open position and a closedposition, comprising an operating member mounted for limited rotationabout the axis of the switch shaft, an oscillating member mounted tomove about a pivot spaced apart from the switch shaft, the saidoscillating member having a slot therein through which the switch shaftpasses so that the movement of the oscillating member about said pivotis limited by the switch shaft, a spring interposed between the free endof said oscillating member and said operating member, the said springbeing put under strain during each movement of the point of connectionof the spring with said operating member toward the line connecting thesaid pivot and the axis of said shaft and released to operate the saidoscillating memher and move said contact mechanism from one of saidpositions to the other during movement of said point of connection ofthe spring with the operating member past the said line.

5. Operating means for an electric switch having a shaft and switchcontact mechanism mounted thereon and operable between an open positionand a closed position, comprising an operating member mounted forlimited rotation about the axis of said shaft, an oscillating membermounted to move abouta pivot spaced apart from the switch shaft, thesaid oscillating member having a slot therein through which the switchshaft passes so that the movement of the oscillating member about saidpivot is limited by the switch shaft, a spring interposed between thefree end of said oscillating member and said operating member, the saidspring being put under strain during each movement of the point ofconnection of the spring with said operating member toward the lineconnecting the said pivot and the axis of said shaft and rethe saidoscillating member and move said contact mechanism from one of saidpositions to the other during movement of said point of connection ofthe spring with the operating member past the said line, and meansoperated by said operating member and coaeting with said oscillatingmember to operate said mechanism to and from said positions in case offailure of said spring.

6. Operating means for an electric switch having a shaft and switchcontact mechanism mounted thereon. and operable between an open positionand a closed position, comprising an operating member mounted for limitshaft, an oscillating member mounted to move about a pivot spaced apartfrom the switch shaft,

the said oscillating member having a slot therein through which theswitch shaft passes so that the movement of the oscillating member aboutsaid pivot is limited by the switch shaft, a spring interposed betweenthe free end of said oscillating member and said operating member, thesaid spring being put under strain during each movement of the point ofconnection of the spring with said operating member toward the lineconnecting the said pivot and the axis of said shaft and released tooperate the said oscillating member and move said contact mechanism fromone of said positions to the other during movementof said point ofconnection of the spring with the operating member past the said line,and

-means operated by said operating member

